Medicare and Medicaid handle networks differently, and the difference matters for where you can go for care

Medicare Part A (hospital) and Part B (doctor visits) do not use a network. You can see any doctor, hospital, or specialist in the United States who accepts Medicare — and most do. There is no list to check, no referral requirement, and no penalty for going out of network because there is no network to begin with.

Medicare Advantage plans (Part C) and Medicare Part D (prescription drugs) do use networks. With Advantage, you pick a plan run by a private insurance company, and that plan has its own list of doctors and hospitals. Part D plans each have their own list of pharmacies and covered drugs. If you go outside the network without approval, you pay more or the plan may not cover the visit at all.

Medicaid networks vary by state and by plan type. Some states let you see any Medicaid provider. Others require you to pick a managed care plan with its own network. The rules depend entirely on where you live and which Medicaid program covers you.

Key Takeaways

  • Original Medicare (Part A and B) has no network — you can see any Medicare-accepting doctor or hospital anywhere in the country.
  • Medicare Advantage plans and Part D drug plans each maintain their own networks, and going outside them costs you more money.
  • Medicaid networks depend on your state and your specific plan; some states have no network requirement, while others require you to choose a managed care plan.
  • Before you enroll in any plan with a network, check whether your current doctors and pharmacies are included.

Original Medicare has no network restrictions

If you have Original Medicare — the standard Part A and Part B coverage run by the federal government — you are not restricted to any network. You can walk into any hospital emergency room, call any cardiologist, or visit any urgent care clinic, as long as that provider accepts Medicare payment. The vast majority do.

This freedom comes with a trade-off: you pay a deductible and coinsurance for each service, and you are responsible for making sure the provider accepts Medicare assignment (meaning they accept Medicare's payment as full payment and do not bill you extra). You can call ahead and ask, or check the Medicare provider search tool at Medicare.gov.

You do not need a referral from a primary care doctor to see a specialist. You do not need permission from an insurance company to have a test or procedure. Original Medicare straightforward pays its share once the service is done.

Medicare Advantage plans use closed networks

If you choose a Medicare Advantage plan (also called Part C), you are switching from Original Medicare to a private insurance plan. That plan has a network — a specific list of doctors, hospitals, and specialists you are supposed to use. The network varies by plan and by region.

When you see an in-network provider, you pay a copay (a fixed amount like $20) or coinsurance (a percentage of the cost). When you see an out-of-network provider, you pay much more — sometimes the full bill — unless it is an emergency. Some Advantage plans do not cover out-of-network care at all except in emergencies.

Most Advantage plans also require you to pick a primary care doctor and get a referral before seeing a specialist. This is different from Original Medicare, where you can see anyone. Before you enroll in an Advantage plan, use the plan's website or call their member services to confirm your doctors are in the network.

Medicare Part D drug plans have pharmacy networks

Medicare Part D is prescription drug coverage. Each Part D plan maintains a list of pharmacies where your prescriptions are covered at the plan's negotiated price. If you fill a prescription at a pharmacy outside the network, you pay the full price and submit a claim for reimbursement — a slow and uncertain process.

Part D plans also maintain a formulary, which is a list of drugs the plan covers. Not every drug is on every formulary, and some drugs require prior approval from the plan before the pharmacy will fill them. You can search the formulary on the plan's website or call the plan to ask whether a specific drug is covered.

If your regular pharmacy or a drug you take is not in the network or formulary, you can ask the plan for an exception, or you can switch to a different Part D plan during the annual enrollment period (October 15 to December 7 each year).

Medicaid networks depend on your state and plan type

Medicaid is a joint federal and state program, so the rules about networks are different in every state. Some states run Medicaid as a fee-for-service program with no network — you can see any Medicaid provider in the state. Other states require most or all Medicaid members to enroll in a managed care plan, which has a network.

If your state uses managed care, you will be assigned to a plan or given a choice of plans. Each plan has its own network of doctors and hospitals. You must use in-network providers except in emergencies, or you will owe the bill yourself. Some states let you stay in fee-for-service Medicaid if you request it, but you have to ask.

Your state's Medicaid website lists which plans are available in your county and which providers are in each network. You can also call your state Medicaid office or a local community health center to find out what type of Medicaid you have and whether you are in a network plan.

How to check if your doctor is in a network

Before you enroll in any plan with a network — Medicare Advantage, Part D, or Medicaid managed care — check whether your current doctors and pharmacy are included. Most plans have a provider search tool on their website. You enter your doctor's name or location, and the tool tells you whether they are in the network.

If the search tool is unclear or does not list your doctor, call the plan's member services number and ask directly. Give them your doctor's full name, address, and phone number. Ask whether the doctor is accepting new patients in that plan and whether any referrals or prior approvals are required.

If your doctor is not in the network and you want to keep seeing them, you have options: you can choose a different plan that includes them, you can ask the plan for an out-of-network exception, or you can stay in Original Medicare (if you have not yet enrolled in Advantage) or fee-for-service Medicaid (if your state offers it).

What happens if you use an out-of-network provider

In Original Medicare, there is no out-of-network penalty because there is no network. You pay the same coinsurance whether the provider is in a "network" or not — because Medicare does not have one.

In Medicare Advantage, using an out-of-network provider usually means you pay a higher copay or coinsurance, or the plan does not cover the visit at all. Emergency room visits are usually covered even if the hospital is out of network, but follow-up care at that same hospital may not be. Check your plan documents or call member services before a planned out-of-network visit.

In Medicaid managed care, going out of network without approval usually means you owe the full bill. Some plans will cover out-of-network emergency care, but you have to pay upfront and then request reimbursement. In fee-for-service Medicaid, there is no network, so this does not explore.

Frequently Asked Questions

Can I see a specialist without a referral in Medicare?

In Original Medicare, yes — you can call any specialist and make an appointment without asking your primary care doctor first. In Medicare Advantage, most plans require a referral from your primary care doctor before they will cover a specialist visit. Check your plan documents or call member services to confirm.

What if my doctor left the Medicare Advantage network?

If your doctor stops accepting your Advantage plan, the plan should notify you. You can switch to a different Advantage plan or go back to Original Medicare during the annual enrollment period (January 1 to March 31). You can also ask the plan whether they will make an exception and continue covering your doctor out of network.

Does Medicaid cover out-of-state providers?

Medicaid is state-based, so coverage usually stops at the state line. If you need care in another state, contact your state Medicaid office before the visit to ask whether they will cover it. Emergency care is usually covered regardless of state, but you may have to pay upfront and request reimbursement.

Can I use the same pharmacy for Medicare Part D and Medicaid?

It depends on the pharmacy and the plans. Some large pharmacies are in both networks. Call your pharmacy and give them your Part D plan name and your Medicaid plan name, and they can tell you whether they accept both. If not, you may need to use different pharmacies for each program.

What if I disagree with a network decision?

If a plan denies coverage because a provider is out of network, you have the right to appeal. Contact the plan's member services and ask for an appeal form. You can also contact your State Health Insurance information Program (SHIP) — a free counseling service — for help with the appeal process.